I. Field of the Invention
The present invention relates generally to power buckets and, more particularly, to a hydraulic actuated power bucket.
II. Description of Related Art
There are many previously known power buckets that are used in a number of applications, such as loading and unloading cargo, underwater dredging, and the like. These previously known power buckets typically comprise two bucket halves that are pivotally mounted together. Each bucket half includes a cutting edge so that the cutting edges are generally parallel to each other.
The bucket halves are movable between an open and a closed position. In the open position, the cutting edges are spaced apart from each other and the bucket halves are pivoted outwardly from each other. When the bucket is moved to a closed position, the bucket halves pivot toward each other thus engulfing the load in between the two bucket halves.
Bucket halves are typically suspended either by a cable or by an excavator stick so that the power bucket is positioned above the load or area to be dredged. Many of the previously known power buckets utilize a plurality of pulleys mounted to the power bucket and which cooperate with a closure line controlled by the operator of the power bucket. Typically, with the power bucket in an open position, the power bucket is closed by pulling the closure line upwardly from the power bucket which causes the power bucket halves to pivot towards each other in the desired fashion.
There have, however, been previously known power buckets which utilized hydraulic actuators to move the power bucket between an open and a closed position. These previously known hydraulic power buckets typically disposed one or more hydraulic cylinders in vertical alignment with the power bucket. The actuation of the hydraulic cylinder would then simulate the movement of the previously known closure line used with power buckets.
These previously known hydraulic power buckets, however, all suffered from a number of common disadvantages. First, for large buckets, e.g. 10 cubic yards or more, it was necessary to use massive hydraulic cylinders to provide sufficient power to close the bucket halves from an open position. Such massive hydraulic cylinders, however, are expensive to manufacture or purchase.
A still further disadvantage of these previously known hydraulic power buckets is that massive hydraulic pumps are required to provide sufficient power to the hydraulic cylinders to open and close the bucket halves. These massive hydraulic pumps are also expensive to obtain and maintain.
A still further disadvantage of these previously known hydraulic power buckets is that the cycle time for closing the power bucket is relatively slow. The relatively slow cycle time for these prior hydraulic power buckets is due primarily to the need to pump hydraulic fluid under high pressure from the compressor and to the hydraulic actuators.
A still further disadvantage of these previously known hydraulic power buckets is that the cutting edges of the power bucket halves vertically dig into the load as the power bucket moves from its open and to its closed position. Typically, the vertical downward displacement of the cutting edges during closing movement of the power bucket exceeds several feet.
While a vertical displacement of the cutting edges of the bucket halves of several feet may be perfectly acceptable for certain operations, such as unloading grain or coal, in other operations it is not. For example, during a dredging operation to remove contaminants from a water bed, it is often desirable to only remove a few inches of the water bed as the power bucket is moved from its open and to its closed position. By removing only a few inches of the water bed during the closure of the power bucket, contaminants on top of the water bed are efficiently removed without removing excessive amounts of the water bed which is uncontaminated. This is particularly important since dump sites which will accept contaminated soil often charge on a volume basis. Consequently, the removal of an excess of uncontaminated waterway escalates the disposal cost of the contaminated material.